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Register a roll once with its outer diameter, core diameter, and full length. CoilCalc calculates material thickness. Next time just enter current diameter to see remaining length.

Yes. Place a coin next to the roll, tap the coin edges on screen for calibration, then tap the roll edges. CoilCalc calculates the real diameter.

Completely. No internet connection, no account, no ads, no subscription.

Any roll or spool: paper, tape, wrap, foil, wire, rope, string, ribbon, film. Built-in presets for common household materials.